/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp

Bug Summary

File:	llvm/lib/Support/VirtualFileSystem.cpp
Warning:	line 1908, column 51 Potential leak of memory pointed to by 'VFS'
Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name VirtualFileSystem.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -fno-split-dwarf-inlining -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-12/lib/clang/12.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/build-llvm/lib/Support -I /build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support -I /build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/build-llvm/include -I /build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-12/lib/clang/12.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/build-llvm/lib/Support -fdebug-prefix-map=/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2020-12-09-025659-44780-1 -x c++ /build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp
1//===- VirtualFileSystem.cpp - Virtual File System Layer ------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the VirtualFileSystem interface.
10//
11//===----------------------------------------------------------------------===//

13#include "llvm/Support/VirtualFileSystem.h"
14#include "llvm/ADT/ArrayRef.h"
15#include "llvm/ADT/DenseMap.h"
16#include "llvm/ADT/IntrusiveRefCntPtr.h"
17#include "llvm/ADT/None.h"
18#include "llvm/ADT/Optional.h"
19#include "llvm/ADT/STLExtras.h"
20#include "llvm/ADT/SmallString.h"
21#include "llvm/ADT/SmallVector.h"
22#include "llvm/ADT/StringRef.h"
23#include "llvm/ADT/StringSet.h"
24#include "llvm/ADT/Twine.h"
25#include "llvm/ADT/iterator_range.h"
26#include "llvm/Config/llvm-config.h"
27#include "llvm/Support/Casting.h"
28#include "llvm/Support/Chrono.h"
29#include "llvm/Support/Compiler.h"
30#include "llvm/Support/Debug.h"
31#include "llvm/Support/Errc.h"
32#include "llvm/Support/ErrorHandling.h"
33#include "llvm/Support/ErrorOr.h"
34#include "llvm/Support/FileSystem.h"
35#include "llvm/Support/MemoryBuffer.h"
36#include "llvm/Support/Path.h"
37#include "llvm/Support/Process.h"
38#include "llvm/Support/SMLoc.h"
39#include "llvm/Support/SourceMgr.h"
40#include "llvm/Support/YAMLParser.h"
41#include "llvm/Support/raw_ostream.h"
42#include <algorithm>
43#include <atomic>
44#include <cassert>
45#include <cstdint>
46#include <iterator>
47#include <limits>
48#include <map>
49#include <memory>
50#include <mutex>
51#include <string>
52#include <system_error>
53#include <utility>
54#include <vector>

56using namespace llvm;
57using namespace llvm::vfs;

59using llvm::sys::fs::file_t;
60using llvm::sys::fs::file_status;
61using llvm::sys::fs::file_type;
62using llvm::sys::fs::kInvalidFile;
63using llvm::sys::fs::perms;
64using llvm::sys::fs::UniqueID;

66Status::Status(const file_status &Status)
  : UID(Status.getUniqueID()), MTime(Status.getLastModificationTime()),
    User(Status.getUser()), Group(Status.getGroup()), Size(Status.getSize()),
    Type(Status.type()), Perms(Status.permissions()) {}

71Status::Status(const Twine &Name, UniqueID UID, sys::TimePoint<> MTime,
             uint32_t User, uint32_t Group, uint64_t Size, file_type Type,
             perms Perms)
  : Name(Name.str()), UID(UID), MTime(MTime), User(User), Group(Group),
    Size(Size), Type(Type), Perms(Perms) {}

77Status Status::copyWithNewName(const Status &In, const Twine &NewName) {
return Status(NewName, In.getUniqueID(), In.getLastModificationTime(),
              In.getUser(), In.getGroup(), In.getSize(), In.getType(),
              In.getPermissions());
81}

83Status Status::copyWithNewName(const file_status &In, const Twine &NewName) {
return Status(NewName, In.getUniqueID(), In.getLastModificationTime(),
              In.getUser(), In.getGroup(), In.getSize(), In.type(),
              In.permissions());
87}

89bool Status::equivalent(const Status &Other) const {
assert(isStatusKnown() && Other.isStatusKnown())((isStatusKnown() && Other.isStatusKnown()) ? static_cast
<void> (0) : __assert_fail ("isStatusKnown() && Other.isStatusKnown()"
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 90, __PRETTY_FUNCTION__));
return getUniqueID() == Other.getUniqueID();
92}

94bool Status::isDirectory() const { return Type == file_type::directory_file; }

96bool Status::isRegularFile() const { return Type == file_type::regular_file; }

98bool Status::isOther() const {
return exists() && !isRegularFile() && !isDirectory() && !isSymlink();
100}

102bool Status::isSymlink() const { return Type == file_type::symlink_file; }

104bool Status::isStatusKnown() const { return Type != file_type::status_error; }

106bool Status::exists() const {
return isStatusKnown() && Type != file_type::file_not_found;
108}

110File::~File() = default;

112FileSystem::~FileSystem() = default;

114ErrorOr<std::unique_ptr<MemoryBuffer>>
115FileSystem::getBufferForFile(const llvm::Twine &Name, int64_t FileSize,
                           bool RequiresNullTerminator, bool IsVolatile) {
auto F = openFileForRead(Name);
if (!F)
  return F.getError();

return (*F)->getBuffer(Name, FileSize, RequiresNullTerminator, IsVolatile);
122}

124std::error_code FileSystem::makeAbsolute(SmallVectorImpl<char> &Path) const {
if (llvm::sys::path::is_absolute(Path))
  return {};

auto WorkingDir = getCurrentWorkingDirectory();
if (!WorkingDir)
  return WorkingDir.getError();

llvm::sys::fs::make_absolute(WorkingDir.get(), Path);
return {};
134}

136std::error_code FileSystem::getRealPath(const Twine &Path,
                                      SmallVectorImpl<char> &Output) const {
return errc::operation_not_permitted;
139}

141std::error_code FileSystem::isLocal(const Twine &Path, bool &Result) {
return errc::operation_not_permitted;
143}

145bool FileSystem::exists(const Twine &Path) {
auto Status = status(Path);
return Status && Status->exists();
148}

150#ifndef NDEBUG
151static bool isTraversalComponent(StringRef Component) {
return Component.equals("..") || Component.equals(".");
153}

155static bool pathHasTraversal(StringRef Path) {
using namespace llvm::sys;

for (StringRef Comp : llvm::make_range(path::begin(Path), path::end(Path)))
  if (isTraversalComponent(Comp))
    return true;
return false;
162}
163#endif

165//===-----------------------------------------------------------------------===/
166// RealFileSystem implementation
167//===-----------------------------------------------------------------------===/

169namespace {

171/// Wrapper around a raw file descriptor.
172class RealFile : public File {
friend class RealFileSystem;

file_t FD;
Status S;
std::string RealName;

RealFile(file_t RawFD, StringRef NewName, StringRef NewRealPathName)
    : FD(RawFD), S(NewName, {}, {}, {}, {}, {},
                   llvm::sys::fs::file_type::status_error, {}),
      RealName(NewRealPathName.str()) {
  assert(FD != kInvalidFile && "Invalid or inactive file descriptor")((FD != kInvalidFile && "Invalid or inactive file descriptor"
) ? static_cast<void> (0) : __assert_fail ("FD != kInvalidFile && \"Invalid or inactive file descriptor\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 183, __PRETTY_FUNCTION__));
}

186public:
~RealFile() override;

ErrorOr<Status> status() override;
ErrorOr<std::string> getName() override;
ErrorOr<std::unique_ptr<MemoryBuffer>> getBuffer(const Twine &Name,
                                                 int64_t FileSize,
                                                 bool RequiresNullTerminator,
                                                 bool IsVolatile) override;
std::error_code close() override;
196};

198} // namespace

200RealFile::~RealFile() { close(); }

202ErrorOr<Status> RealFile::status() {
assert(FD != kInvalidFile && "cannot stat closed file")((FD != kInvalidFile && "cannot stat closed file") ? static_cast
<void> (0) : __assert_fail ("FD != kInvalidFile && \"cannot stat closed file\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 203, __PRETTY_FUNCTION__));
if (!S.isStatusKnown()) {
  file_status RealStatus;
  if (std::error_code EC = sys::fs::status(FD, RealStatus))
    return EC;
  S = Status::copyWithNewName(RealStatus, S.getName());
}
return S;
211}

213ErrorOr<std::string> RealFile::getName() {
return RealName.empty() ? S.getName().str() : RealName;
215}

217ErrorOr<std::unique_ptr<MemoryBuffer>>
218RealFile::getBuffer(const Twine &Name, int64_t FileSize,
                  bool RequiresNullTerminator, bool IsVolatile) {
assert(FD != kInvalidFile && "cannot get buffer for closed file")((FD != kInvalidFile && "cannot get buffer for closed file"
) ? static_cast<void> (0) : __assert_fail ("FD != kInvalidFile && \"cannot get buffer for closed file\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 220, __PRETTY_FUNCTION__));
return MemoryBuffer::getOpenFile(FD, Name, FileSize, RequiresNullTerminator,
                                 IsVolatile);
223}

225std::error_code RealFile::close() {
std::error_code EC = sys::fs::closeFile(FD);
FD = kInvalidFile;
return EC;
229}

231namespace {

233/// A file system according to your operating system.
234/// This may be linked to the process's working directory, or maintain its own.
235///
236/// Currently, its own working directory is emulated by storing the path and
237/// sending absolute paths to llvm::sys::fs:: functions.
238/// A more principled approach would be to push this down a level, modelling
239/// the working dir as an llvm::sys::fs::WorkingDir or similar.
240/// This would enable the use of openat()-style functions on some platforms.
241class RealFileSystem : public FileSystem {
242public:
explicit RealFileSystem(bool LinkCWDToProcess) {
  if (!LinkCWDToProcess) {
    SmallString<128> PWD, RealPWD;
    if (llvm::sys::fs::current_path(PWD))
      return; // Awful, but nothing to do here.
    if (llvm::sys::fs::real_path(PWD, RealPWD))
      WD = {PWD, PWD};
    else
      WD = {PWD, RealPWD};
  }
}

ErrorOr<Status> status(const Twine &Path) override;
ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override;
directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;

llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
std::error_code isLocal(const Twine &Path, bool &Result) override;
std::error_code getRealPath(const Twine &Path,
                            SmallVectorImpl<char> &Output) const override;

265private:
// If this FS has its own working dir, use it to make Path absolute.
// The returned twine is safe to use as long as both Storage and Path live.
Twine adjustPath(const Twine &Path, SmallVectorImpl<char> &Storage) const {
  if (!WD)
    return Path;
  Path.toVector(Storage);
  sys::fs::make_absolute(WD->Resolved, Storage);
  return Storage;
}

struct WorkingDirectory {
  // The current working directory, without symlinks resolved. (echo $PWD).
  SmallString<128> Specified;
  // The current working directory, with links resolved. (readlink .).
  SmallString<128> Resolved;
};
Optional<WorkingDirectory> WD;
283};

285} // namespace

287ErrorOr<Status> RealFileSystem::status(const Twine &Path) {
SmallString<256> Storage;
sys::fs::file_status RealStatus;
if (std::error_code EC =
        sys::fs::status(adjustPath(Path, Storage), RealStatus))
  return EC;
return Status::copyWithNewName(RealStatus, Path);
294}

296ErrorOr<std::unique_ptr<File>>
297RealFileSystem::openFileForRead(const Twine &Name) {
SmallString<256> RealName, Storage;
Expected<file_t> FDOrErr = sys::fs::openNativeFileForRead(
    adjustPath(Name, Storage), sys::fs::OF_None, &RealName);
if (!FDOrErr)
  return errorToErrorCode(FDOrErr.takeError());
return std::unique_ptr<File>(
    new RealFile(*FDOrErr, Name.str(), RealName.str()));
305}

307llvm::ErrorOr<std::string> RealFileSystem::getCurrentWorkingDirectory() const {
if (WD)
  return std::string(WD->Specified.str());

SmallString<128> Dir;
if (std::error_code EC = llvm::sys::fs::current_path(Dir))
  return EC;
return std::string(Dir.str());
315}

317std::error_code RealFileSystem::setCurrentWorkingDirectory(const Twine &Path) {
if (!WD)
  return llvm::sys::fs::set_current_path(Path);

SmallString<128> Absolute, Resolved, Storage;
adjustPath(Path, Storage).toVector(Absolute);
bool IsDir;
if (auto Err = llvm::sys::fs::is_directory(Absolute, IsDir))
  return Err;
if (!IsDir)
  return std::make_error_code(std::errc::not_a_directory);
if (auto Err = llvm::sys::fs::real_path(Absolute, Resolved))
  return Err;
WD = {Absolute, Resolved};
return std::error_code();
332}

334std::error_code RealFileSystem::isLocal(const Twine &Path, bool &Result) {
SmallString<256> Storage;
return llvm::sys::fs::is_local(adjustPath(Path, Storage), Result);
337}

339std::error_code
340RealFileSystem::getRealPath(const Twine &Path,
                          SmallVectorImpl<char> &Output) const {
SmallString<256> Storage;
return llvm::sys::fs::real_path(adjustPath(Path, Storage), Output);
344}

346IntrusiveRefCntPtr<FileSystem> vfs::getRealFileSystem() {
static IntrusiveRefCntPtr<FileSystem> FS(new RealFileSystem(true));
return FS;
349}

351std::unique_ptr<FileSystem> vfs::createPhysicalFileSystem() {
return std::make_unique<RealFileSystem>(false);
353}

355namespace {

357class RealFSDirIter : public llvm::vfs::detail::DirIterImpl {
llvm::sys::fs::directory_iterator Iter;

360public:
RealFSDirIter(const Twine &Path, std::error_code &EC) : Iter(Path, EC) {
  if (Iter != llvm::sys::fs::directory_iterator())
    CurrentEntry = directory_entry(Iter->path(), Iter->type());
}

std::error_code increment() override {
  std::error_code EC;
  Iter.increment(EC);
  CurrentEntry = (Iter == llvm::sys::fs::directory_iterator())
                     ? directory_entry()
                     : directory_entry(Iter->path(), Iter->type());
  return EC;
}
374};

376} // namespace

378directory_iterator RealFileSystem::dir_begin(const Twine &Dir,
                                           std::error_code &EC) {
SmallString<128> Storage;
return directory_iterator(
    std::make_shared<RealFSDirIter>(adjustPath(Dir, Storage), EC));
383}

385//===-----------------------------------------------------------------------===/
386// OverlayFileSystem implementation
387//===-----------------------------------------------------------------------===/

389OverlayFileSystem::OverlayFileSystem(IntrusiveRefCntPtr<FileSystem> BaseFS) {
FSList.push_back(std::move(BaseFS));
391}

393void OverlayFileSystem::pushOverlay(IntrusiveRefCntPtr<FileSystem> FS) {
FSList.push_back(FS);
// Synchronize added file systems by duplicating the working directory from
// the first one in the list.
FS->setCurrentWorkingDirectory(getCurrentWorkingDirectory().get());
398}

400ErrorOr<Status> OverlayFileSystem::status(const Twine &Path) {
// FIXME: handle symlinks that cross file systems
for (iterator I = overlays_begin(), E = overlays_end(); I != E; ++I) {
  ErrorOr<Status> Status = (*I)->status(Path);
  if (Status || Status.getError() != llvm::errc::no_such_file_or_directory)
    return Status;
}
return make_error_code(llvm::errc::no_such_file_or_directory);
408}

410ErrorOr<std::unique_ptr<File>>
411OverlayFileSystem::openFileForRead(const llvm::Twine &Path) {
// FIXME: handle symlinks that cross file systems
for (iterator I = overlays_begin(), E = overlays_end(); I != E; ++I) {
  auto Result = (*I)->openFileForRead(Path);
  if (Result || Result.getError() != llvm::errc::no_such_file_or_directory)
    return Result;
}
return make_error_code(llvm::errc::no_such_file_or_directory);
419}

421llvm::ErrorOr<std::string>
422OverlayFileSystem::getCurrentWorkingDirectory() const {
// All file systems are synchronized, just take the first working directory.
return FSList.front()->getCurrentWorkingDirectory();
425}

427std::error_code
428OverlayFileSystem::setCurrentWorkingDirectory(const Twine &Path) {
for (auto &FS : FSList)
  if (std::error_code EC = FS->setCurrentWorkingDirectory(Path))
    return EC;
return {};
433}

435std::error_code OverlayFileSystem::isLocal(const Twine &Path, bool &Result) {
for (auto &FS : FSList)
  if (FS->exists(Path))
    return FS->isLocal(Path, Result);
return errc::no_such_file_or_directory;
440}

442std::error_code
443OverlayFileSystem::getRealPath(const Twine &Path,
                             SmallVectorImpl<char> &Output) const {
for (auto &FS : FSList)
  if (FS->exists(Path))
    return FS->getRealPath(Path, Output);
return errc::no_such_file_or_directory;
449}

451llvm::vfs::detail::DirIterImpl::~DirIterImpl() = default;

453namespace {

455class OverlayFSDirIterImpl : public llvm::vfs::detail::DirIterImpl {
OverlayFileSystem &Overlays;
std::string Path;
OverlayFileSystem::iterator CurrentFS;
directory_iterator CurrentDirIter;
llvm::StringSet<> SeenNames;

std::error_code incrementFS() {
  assert(CurrentFS != Overlays.overlays_end() && "incrementing past end")((CurrentFS != Overlays.overlays_end() && "incrementing past end"
) ? static_cast<void> (0) : __assert_fail ("CurrentFS != Overlays.overlays_end() && \"incrementing past end\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 463, __PRETTY_FUNCTION__));
  ++CurrentFS;
  for (auto E = Overlays.overlays_end(); CurrentFS != E; ++CurrentFS) {
    std::error_code EC;
    CurrentDirIter = (*CurrentFS)->dir_begin(Path, EC);
    if (EC && EC != errc::no_such_file_or_directory)
      return EC;
    if (CurrentDirIter != directory_iterator())
      break; // found
  }
  return {};
}

std::error_code incrementDirIter(bool IsFirstTime) {
  assert((IsFirstTime || CurrentDirIter != directory_iterator()) &&(((IsFirstTime || CurrentDirIter != directory_iterator()) &&
 "incrementing past end") ? static_cast<void> (0) : __assert_fail
 ("(IsFirstTime || CurrentDirIter != directory_iterator()) && \"incrementing past end\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 478, __PRETTY_FUNCTION__))
         "incrementing past end")(((IsFirstTime || CurrentDirIter != directory_iterator()) &&
 "incrementing past end") ? static_cast<void> (0) : __assert_fail
 ("(IsFirstTime || CurrentDirIter != directory_iterator()) && \"incrementing past end\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 478, __PRETTY_FUNCTION__));
  std::error_code EC;
  if (!IsFirstTime)
    CurrentDirIter.increment(EC);
  if (!EC && CurrentDirIter == directory_iterator())
    EC = incrementFS();
  return EC;
}

std::error_code incrementImpl(bool IsFirstTime) {
  while (true) {
    std::error_code EC = incrementDirIter(IsFirstTime);
    if (EC || CurrentDirIter == directory_iterator()) {
      CurrentEntry = directory_entry();
      return EC;
    }
    CurrentEntry = *CurrentDirIter;
    StringRef Name = llvm::sys::path::filename(CurrentEntry.path());
    if (SeenNames.insert(Name).second)
      return EC; // name not seen before
  }
  llvm_unreachable("returned above")::llvm::llvm_unreachable_internal("returned above", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 499);
}

502public:
OverlayFSDirIterImpl(const Twine &Path, OverlayFileSystem &FS,
                     std::error_code &EC)
    : Overlays(FS), Path(Path.str()), CurrentFS(Overlays.overlays_begin()) {
  CurrentDirIter = (*CurrentFS)->dir_begin(Path, EC);
  EC = incrementImpl(true);
}

std::error_code increment() override { return incrementImpl(false); }
511};

513} // namespace

515directory_iterator OverlayFileSystem::dir_begin(const Twine &Dir,
                                              std::error_code &EC) {
return directory_iterator(
    std::make_shared<OverlayFSDirIterImpl>(Dir, *this, EC));
519}

521void ProxyFileSystem::anchor() {}

523namespace llvm {
524namespace vfs {

526namespace detail {

528enum InMemoryNodeKind { IME_File, IME_Directory, IME_HardLink };

530/// The in memory file system is a tree of Nodes. Every node can either be a
531/// file , hardlink or a directory.
532class InMemoryNode {
InMemoryNodeKind Kind;
std::string FileName;

536public:
InMemoryNode(llvm::StringRef FileName, InMemoryNodeKind Kind)
    : Kind(Kind), FileName(std::string(llvm::sys::path::filename(FileName))) {
}
virtual ~InMemoryNode() = default;

/// Get the filename of this node (the name without the directory part).
StringRef getFileName() const { return FileName; }
InMemoryNodeKind getKind() const { return Kind; }
virtual std::string toString(unsigned Indent) const = 0;
546};

548class InMemoryFile : public InMemoryNode {
Status Stat;
std::unique_ptr<llvm::MemoryBuffer> Buffer;

552public:
InMemoryFile(Status Stat, std::unique_ptr<llvm::MemoryBuffer> Buffer)
    : InMemoryNode(Stat.getName(), IME_File), Stat(std::move(Stat)),
      Buffer(std::move(Buffer)) {}

/// Return the \p Status for this node. \p RequestedName should be the name
/// through which the caller referred to this node. It will override
/// \p Status::Name in the return value, to mimic the behavior of \p RealFile.
Status getStatus(const Twine &RequestedName) const {
  return Status::copyWithNewName(Stat, RequestedName);
}
llvm::MemoryBuffer *getBuffer() const { return Buffer.get(); }

std::string toString(unsigned Indent) const override {
  return (std::string(Indent, ' ') + Stat.getName() + "\n").str();
}

static bool classof(const InMemoryNode *N) {
  return N->getKind() == IME_File;
}
572};

574namespace {

576class InMemoryHardLink : public InMemoryNode {
const InMemoryFile &ResolvedFile;

579public:
InMemoryHardLink(StringRef Path, const InMemoryFile &ResolvedFile)
    : InMemoryNode(Path, IME_HardLink), ResolvedFile(ResolvedFile) {}
const InMemoryFile &getResolvedFile() const { return ResolvedFile; }

std::string toString(unsigned Indent) const override {
  return std::string(Indent, ' ') + "HardLink to -> " +
         ResolvedFile.toString(0);
}

static bool classof(const InMemoryNode *N) {
  return N->getKind() == IME_HardLink;
}
592};

594/// Adapt a InMemoryFile for VFS' File interface.  The goal is to make
595/// \p InMemoryFileAdaptor mimic as much as possible the behavior of
596/// \p RealFile.
597class InMemoryFileAdaptor : public File {
const InMemoryFile &Node;
/// The name to use when returning a Status for this file.
std::string RequestedName;

602public:
explicit InMemoryFileAdaptor(const InMemoryFile &Node,
                             std::string RequestedName)
    : Node(Node), RequestedName(std::move(RequestedName)) {}

llvm::ErrorOr<Status> status() override {
  return Node.getStatus(RequestedName);
}

llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
getBuffer(const Twine &Name, int64_t FileSize, bool RequiresNullTerminator,
          bool IsVolatile) override {
  llvm::MemoryBuffer *Buf = Node.getBuffer();
  return llvm::MemoryBuffer::getMemBuffer(
      Buf->getBuffer(), Buf->getBufferIdentifier(), RequiresNullTerminator);
}

std::error_code close() override { return {}; }
620};
621} // namespace

623class InMemoryDirectory : public InMemoryNode {
Status Stat;
llvm::StringMap<std::unique_ptr<InMemoryNode>> Entries;

627public:
InMemoryDirectory(Status Stat)
    : InMemoryNode(Stat.getName(), IME_Directory), Stat(std::move(Stat)) {}

/// Return the \p Status for this node. \p RequestedName should be the name
/// through which the caller referred to this node. It will override
/// \p Status::Name in the return value, to mimic the behavior of \p RealFile.
Status getStatus(const Twine &RequestedName) const {
  return Status::copyWithNewName(Stat, RequestedName);
}
InMemoryNode *getChild(StringRef Name) {
  auto I = Entries.find(Name);
  if (I != Entries.end())
    return I->second.get();
  return nullptr;
}

InMemoryNode *addChild(StringRef Name, std::unique_ptr<InMemoryNode> Child) {
  return Entries.insert(make_pair(Name, std::move(Child)))
      .first->second.get();
}

using const_iterator = decltype(Entries)::const_iterator;

const_iterator begin() const { return Entries.begin(); }
const_iterator end() const { return Entries.end(); }

std::string toString(unsigned Indent) const override {
  std::string Result =
      (std::string(Indent, ' ') + Stat.getName() + "\n").str();
  for (const auto &Entry : Entries)
    Result += Entry.second->toString(Indent + 2);
  return Result;
}

static bool classof(const InMemoryNode *N) {
  return N->getKind() == IME_Directory;
}
665};

667namespace {
668Status getNodeStatus(const InMemoryNode *Node, const Twine &RequestedName) {
if (auto Dir = dyn_cast<detail::InMemoryDirectory>(Node))
  return Dir->getStatus(RequestedName);
if (auto File = dyn_cast<detail::InMemoryFile>(Node))
  return File->getStatus(RequestedName);
if (auto Link = dyn_cast<detail::InMemoryHardLink>(Node))
  return Link->getResolvedFile().getStatus(RequestedName);
llvm_unreachable("Unknown node type")::llvm::llvm_unreachable_internal("Unknown node type", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 675);
676}
677} // namespace
678} // namespace detail

680InMemoryFileSystem::InMemoryFileSystem(bool UseNormalizedPaths)
  : Root(new detail::InMemoryDirectory(
        Status("", getNextVirtualUniqueID(), llvm::sys::TimePoint<>(), 0, 0,
               0, llvm::sys::fs::file_type::directory_file,
               llvm::sys::fs::perms::all_all))),
    UseNormalizedPaths(UseNormalizedPaths) {}

687InMemoryFileSystem::~InMemoryFileSystem() = default;

689std::string InMemoryFileSystem::toString() const {
return Root->toString(/*Indent=*/0);
691}

693bool InMemoryFileSystem::addFile(const Twine &P, time_t ModificationTime,
                               std::unique_ptr<llvm::MemoryBuffer> Buffer,
                               Optional<uint32_t> User,
                               Optional<uint32_t> Group,
                               Optional<llvm::sys::fs::file_type> Type,
                               Optional<llvm::sys::fs::perms> Perms,
                               const detail::InMemoryFile *HardLinkTarget) {
SmallString<128> Path;
P.toVector(Path);

// Fix up relative paths. This just prepends the current working directory.
std::error_code EC = makeAbsolute(Path);
assert(!EC)((!EC) ? static_cast<void> (0) : __assert_fail ("!EC", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 705, __PRETTY_FUNCTION__));
(void)EC;

if (useNormalizedPaths())
  llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);

if (Path.empty())
  return false;

detail::InMemoryDirectory *Dir = Root.get();
auto I = llvm::sys::path::begin(Path), E = sys::path::end(Path);
const auto ResolvedUser = User.getValueOr(0);
const auto ResolvedGroup = Group.getValueOr(0);
const auto ResolvedType = Type.getValueOr(sys::fs::file_type::regular_file);
const auto ResolvedPerms = Perms.getValueOr(sys::fs::all_all);
assert(!(HardLinkTarget && Buffer) && "HardLink cannot have a buffer")((!(HardLinkTarget && Buffer) && "HardLink cannot have a buffer"
) ? static_cast<void> (0) : __assert_fail ("!(HardLinkTarget && Buffer) && \"HardLink cannot have a buffer\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 720, __PRETTY_FUNCTION__));
// Any intermediate directories we create should be accessible by
// the owner, even if Perms says otherwise for the final path.
const auto NewDirectoryPerms = ResolvedPerms | sys::fs::owner_all;
while (true) {
  StringRef Name = *I;
  detail::InMemoryNode *Node = Dir->getChild(Name);
  ++I;
  if (!Node) {
    if (I == E) {
      // End of the path.
      std::unique_ptr<detail::InMemoryNode> Child;
      if (HardLinkTarget)
        Child.reset(new detail::InMemoryHardLink(P.str(), *HardLinkTarget));
      else {
        // Create a new file or directory.
        Status Stat(P.str(), getNextVirtualUniqueID(),
                    llvm::sys::toTimePoint(ModificationTime), ResolvedUser,
                    ResolvedGroup, Buffer->getBufferSize(), ResolvedType,
                    ResolvedPerms);
        if (ResolvedType == sys::fs::file_type::directory_file) {
          Child.reset(new detail::InMemoryDirectory(std::move(Stat)));
        } else {
          Child.reset(
              new detail::InMemoryFile(std::move(Stat), std::move(Buffer)));
        }
      }
      Dir->addChild(Name, std::move(Child));
      return true;
    }

    // Create a new directory. Use the path up to here.
    Status Stat(
        StringRef(Path.str().begin(), Name.end() - Path.str().begin()),
        getNextVirtualUniqueID(), llvm::sys::toTimePoint(ModificationTime),
        ResolvedUser, ResolvedGroup, 0, sys::fs::file_type::directory_file,
        NewDirectoryPerms);
    Dir = cast<detail::InMemoryDirectory>(Dir->addChild(
        Name, std::make_unique<detail::InMemoryDirectory>(std::move(Stat))));
    continue;
  }

  if (auto *NewDir = dyn_cast<detail::InMemoryDirectory>(Node)) {
    Dir = NewDir;
  } else {
    assert((isa<detail::InMemoryFile>(Node) ||(((isa<detail::InMemoryFile>(Node) || isa<detail::InMemoryHardLink
>(Node)) && "Must be either file, hardlink or directory!"
) ? static_cast<void> (0) : __assert_fail ("(isa<detail::InMemoryFile>(Node) || isa<detail::InMemoryHardLink>(Node)) && \"Must be either file, hardlink or directory!\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 767, __PRETTY_FUNCTION__))
            isa<detail::InMemoryHardLink>(Node)) &&(((isa<detail::InMemoryFile>(Node) || isa<detail::InMemoryHardLink
>(Node)) && "Must be either file, hardlink or directory!"
) ? static_cast<void> (0) : __assert_fail ("(isa<detail::InMemoryFile>(Node) || isa<detail::InMemoryHardLink>(Node)) && \"Must be either file, hardlink or directory!\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 767, __PRETTY_FUNCTION__))
           "Must be either file, hardlink or directory!")(((isa<detail::InMemoryFile>(Node) || isa<detail::InMemoryHardLink
>(Node)) && "Must be either file, hardlink or directory!"
) ? static_cast<void> (0) : __assert_fail ("(isa<detail::InMemoryFile>(Node) || isa<detail::InMemoryHardLink>(Node)) && \"Must be either file, hardlink or directory!\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 767, __PRETTY_FUNCTION__));

    // Trying to insert a directory in place of a file.
    if (I != E)
      return false;

    // Return false only if the new file is different from the existing one.
    if (auto Link = dyn_cast<detail::InMemoryHardLink>(Node)) {
      return Link->getResolvedFile().getBuffer()->getBuffer() ==
             Buffer->getBuffer();
    }
    return cast<detail::InMemoryFile>(Node)->getBuffer()->getBuffer() ==
           Buffer->getBuffer();
  }
}
782}

784bool InMemoryFileSystem::addFile(const Twine &P, time_t ModificationTime,
                               std::unique_ptr<llvm::MemoryBuffer> Buffer,
                               Optional<uint32_t> User,
                               Optional<uint32_t> Group,
                               Optional<llvm::sys::fs::file_type> Type,
                               Optional<llvm::sys::fs::perms> Perms) {
return addFile(P, ModificationTime, std::move(Buffer), User, Group, Type,
               Perms, /*HardLinkTarget=*/nullptr);
792}

794bool InMemoryFileSystem::addFileNoOwn(const Twine &P, time_t ModificationTime,
                                    const llvm::MemoryBufferRef &Buffer,
                                    Optional<uint32_t> User,
                                    Optional<uint32_t> Group,
                                    Optional<llvm::sys::fs::file_type> Type,
                                    Optional<llvm::sys::fs::perms> Perms) {
return addFile(P, ModificationTime, llvm::MemoryBuffer::getMemBuffer(Buffer),
               std::move(User), std::move(Group), std::move(Type),
               std::move(Perms));
803}

805static ErrorOr<const detail::InMemoryNode *>
806lookupInMemoryNode(const InMemoryFileSystem &FS, detail::InMemoryDirectory *Dir,
                 const Twine &P) {
SmallString<128> Path;
P.toVector(Path);

// Fix up relative paths. This just prepends the current working directory.
std::error_code EC = FS.makeAbsolute(Path);
assert(!EC)((!EC) ? static_cast<void> (0) : __assert_fail ("!EC", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 813, __PRETTY_FUNCTION__));
(void)EC;

if (FS.useNormalizedPaths())
  llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);

if (Path.empty())
  return Dir;

auto I = llvm::sys::path::begin(Path), E = llvm::sys::path::end(Path);
while (true) {
  detail::InMemoryNode *Node = Dir->getChild(*I);
  ++I;
  if (!Node)
    return errc::no_such_file_or_directory;

  // Return the file if it's at the end of the path.
  if (auto File = dyn_cast<detail::InMemoryFile>(Node)) {
    if (I == E)
      return File;
    return errc::no_such_file_or_directory;
  }

  // If Node is HardLink then return the resolved file.
  if (auto File = dyn_cast<detail::InMemoryHardLink>(Node)) {
    if (I == E)
      return &File->getResolvedFile();
    return errc::no_such_file_or_directory;
  }
  // Traverse directories.
  Dir = cast<detail::InMemoryDirectory>(Node);
  if (I == E)
    return Dir;
}
847}

849bool InMemoryFileSystem::addHardLink(const Twine &FromPath,
                                   const Twine &ToPath) {
auto FromNode = lookupInMemoryNode(*this, Root.get(), FromPath);
auto ToNode = lookupInMemoryNode(*this, Root.get(), ToPath);
// FromPath must not have been added before. ToPath must have been added
// before. Resolved ToPath must be a File.
if (!ToNode || FromNode || !isa<detail::InMemoryFile>(*ToNode))
  return false;
return this->addFile(FromPath, 0, nullptr, None, None, None, None,
                     cast<detail::InMemoryFile>(*ToNode));
859}

861llvm::ErrorOr<Status> InMemoryFileSystem::status(const Twine &Path) {
auto Node = lookupInMemoryNode(*this, Root.get(), Path);
if (Node)
  return detail::getNodeStatus(*Node, Path);
return Node.getError();
866}

868llvm::ErrorOr<std::unique_ptr<File>>
869InMemoryFileSystem::openFileForRead(const Twine &Path) {
auto Node = lookupInMemoryNode(*this, Root.get(), Path);
if (!Node)
  return Node.getError();

// When we have a file provide a heap-allocated wrapper for the memory buffer
// to match the ownership semantics for File.
if (auto *F = dyn_cast<detail::InMemoryFile>(*Node))
  return std::unique_ptr<File>(
      new detail::InMemoryFileAdaptor(*F, Path.str()));

// FIXME: errc::not_a_file?
return make_error_code(llvm::errc::invalid_argument);
882}

884namespace {

886/// Adaptor from InMemoryDir::iterator to directory_iterator.
887class InMemoryDirIterator : public llvm::vfs::detail::DirIterImpl {
detail::InMemoryDirectory::const_iterator I;
detail::InMemoryDirectory::const_iterator E;
std::string RequestedDirName;

void setCurrentEntry() {
  if (I != E) {
    SmallString<256> Path(RequestedDirName);
    llvm::sys::path::append(Path, I->second->getFileName());
    sys::fs::file_type Type = sys::fs::file_type::type_unknown;
    switch (I->second->getKind()) {
    case detail::IME_File:
    case detail::IME_HardLink:
      Type = sys::fs::file_type::regular_file;
      break;
    case detail::IME_Directory:
      Type = sys::fs::file_type::directory_file;
      break;
    }
    CurrentEntry = directory_entry(std::string(Path.str()), Type);
  } else {
    // When we're at the end, make CurrentEntry invalid and DirIterImpl will
    // do the rest.
    CurrentEntry = directory_entry();
  }
}

914public:
InMemoryDirIterator() = default;

explicit InMemoryDirIterator(const detail::InMemoryDirectory &Dir,
                             std::string RequestedDirName)
    : I(Dir.begin()), E(Dir.end()),
      RequestedDirName(std::move(RequestedDirName)) {
  setCurrentEntry();
}

std::error_code increment() override {
  ++I;
  setCurrentEntry();
  return {};
}
929};

931} // namespace

933directory_iterator InMemoryFileSystem::dir_begin(const Twine &Dir,
                                               std::error_code &EC) {
auto Node = lookupInMemoryNode(*this, Root.get(), Dir);
if (!Node) {
  EC = Node.getError();
  return directory_iterator(std::make_shared<InMemoryDirIterator>());
}

if (auto *DirNode = dyn_cast<detail::InMemoryDirectory>(*Node))
  return directory_iterator(
      std::make_shared<InMemoryDirIterator>(*DirNode, Dir.str()));

EC = make_error_code(llvm::errc::not_a_directory);
return directory_iterator(std::make_shared<InMemoryDirIterator>());
947}

949std::error_code InMemoryFileSystem::setCurrentWorkingDirectory(const Twine &P) {
SmallString<128> Path;
P.toVector(Path);

// Fix up relative paths. This just prepends the current working directory.
std::error_code EC = makeAbsolute(Path);
assert(!EC)((!EC) ? static_cast<void> (0) : __assert_fail ("!EC", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 955, __PRETTY_FUNCTION__));
(void)EC;

if (useNormalizedPaths())
  llvm::sys::path::remove_dots(Path, /*remove_dot_dot=*/true);

if (!Path.empty())
  WorkingDirectory = std::string(Path.str());
return {};
964}

966std::error_code
967InMemoryFileSystem::getRealPath(const Twine &Path,
                              SmallVectorImpl<char> &Output) const {
auto CWD = getCurrentWorkingDirectory();
if (!CWD || CWD->empty())
  return errc::operation_not_permitted;
Path.toVector(Output);
if (auto EC = makeAbsolute(Output))
  return EC;
llvm::sys::path::remove_dots(Output, /*remove_dot_dot=*/true);
return {};
977}

979std::error_code InMemoryFileSystem::isLocal(const Twine &Path, bool &Result) {
Result = false;
return {};
982}

984} // namespace vfs
985} // namespace llvm

987//===-----------------------------------------------------------------------===/
988// RedirectingFileSystem implementation
989//===-----------------------------------------------------------------------===/

991namespace {

993/// Removes leading "./" as well as path components like ".." and ".".
994static llvm::SmallString<256> canonicalize(llvm::StringRef Path) {
// First detect the path style in use by checking the first separator.
llvm::sys::path::Style style = llvm::sys::path::Style::native;
const size_t n = Path.find_first_of("/\\");
if (n != static_cast<size_t>(-1))
  style = (Path[n] == '/') ? llvm::sys::path::Style::posix
                           : llvm::sys::path::Style::windows;

// Now remove the dots.  Explicitly specifying the path style prevents the
// direction of the slashes from changing.
llvm::SmallString<256> result =
    llvm::sys::path::remove_leading_dotslash(Path, style);
llvm::sys::path::remove_dots(result, /*remove_dot_dot=*/true, style);
return result;
1008}

1010} // anonymous namespace


1013RedirectingFileSystem::RedirectingFileSystem(IntrusiveRefCntPtr<FileSystem> FS)
  : ExternalFS(std::move(FS)) {
if (ExternalFS)
  if (auto ExternalWorkingDirectory =
          ExternalFS->getCurrentWorkingDirectory()) {
    WorkingDirectory = *ExternalWorkingDirectory;
    ExternalFSValidWD = true;
  }
1021}

1023// FIXME: reuse implementation common with OverlayFSDirIterImpl as these
1024// iterators are conceptually similar.
1025class llvm::vfs::VFSFromYamlDirIterImpl
  : public llvm::vfs::detail::DirIterImpl {
std::string Dir;
RedirectingFileSystem::RedirectingDirectoryEntry::iterator Current, End;

// To handle 'fallthrough' mode we need to iterate at first through
// RedirectingDirectoryEntry and then through ExternalFS. These operations are
// done sequentially, we just need to keep a track of what kind of iteration
// we are currently performing.

/// Flag telling if we should iterate through ExternalFS or stop at the last
/// RedirectingDirectoryEntry::iterator.
bool IterateExternalFS;
/// Flag telling if we have switched to iterating through ExternalFS.
bool IsExternalFSCurrent = false;
FileSystem &ExternalFS;
directory_iterator ExternalDirIter;
llvm::StringSet<> SeenNames;

/// To combine multiple iterations, different methods are responsible for
/// different iteration steps.
/// @{

/// Responsible for dispatching between RedirectingDirectoryEntry iteration
/// and ExternalFS iteration.
std::error_code incrementImpl(bool IsFirstTime);
/// Responsible for RedirectingDirectoryEntry iteration.
std::error_code incrementContent(bool IsFirstTime);
/// Responsible for ExternalFS iteration.
std::error_code incrementExternal();
/// @}

1057public:
VFSFromYamlDirIterImpl(
    const Twine &Path,
    RedirectingFileSystem::RedirectingDirectoryEntry::iterator Begin,
    RedirectingFileSystem::RedirectingDirectoryEntry::iterator End,
    bool IterateExternalFS, FileSystem &ExternalFS, std::error_code &EC);

std::error_code increment() override;
1065};

1067llvm::ErrorOr<std::string>
1068RedirectingFileSystem::getCurrentWorkingDirectory() const {
return WorkingDirectory;
1070}

1072std::error_code
1073RedirectingFileSystem::setCurrentWorkingDirectory(const Twine &Path) {
// Don't change the working directory if the path doesn't exist.
if (!exists(Path))
  return errc::no_such_file_or_directory;

// Always change the external FS but ignore its result.
if (ExternalFS) {
  auto EC = ExternalFS->setCurrentWorkingDirectory(Path);
  ExternalFSValidWD = !static_cast<bool>(EC);
}

SmallString<128> AbsolutePath;
Path.toVector(AbsolutePath);
if (std::error_code EC = makeAbsolute(AbsolutePath))
  return EC;
WorkingDirectory = std::string(AbsolutePath.str());
return {};
1090}

1092std::error_code RedirectingFileSystem::isLocal(const Twine &Path,
                                             bool &Result) {
return ExternalFS->isLocal(Path, Result);
1095}

1097std::error_code RedirectingFileSystem::makeAbsolute(SmallVectorImpl<char> &Path) const {
if (llvm::sys::path::is_absolute(Path, llvm::sys::path::Style::posix) ||
    llvm::sys::path::is_absolute(Path, llvm::sys::path::Style::windows))
  return {};

auto WorkingDir = getCurrentWorkingDirectory();
if (!WorkingDir)
  return WorkingDir.getError();

// We can't use sys::fs::make_absolute because that assumes the path style
// is native and there is no way to override that.  Since we know WorkingDir
// is absolute, we can use it to determine which style we actually have and
// append Path ourselves.
sys::path::Style style = sys::path::Style::windows;
if (sys::path::is_absolute(WorkingDir.get(), sys::path::Style::posix)) {
  style = sys::path::Style::posix;
}

std::string Result = WorkingDir.get();
StringRef Dir(Result);
if (!Dir.endswith(sys::path::get_separator(style))) {
  Result += sys::path::get_separator(style);
}
Result.append(Path.data(), Path.size());
Path.assign(Result.begin(), Result.end());

return {};
1124}

1126directory_iterator RedirectingFileSystem::dir_begin(const Twine &Dir,
                                                  std::error_code &EC) {
ErrorOr<RedirectingFileSystem::Entry *> E = lookupPath(Dir);
if (!E) {
  EC = E.getError();
  if (shouldUseExternalFS() && EC == errc::no_such_file_or_directory)
    return ExternalFS->dir_begin(Dir, EC);
  return {};
}
ErrorOr<Status> S = status(Dir, *E);
if (!S) {
  EC = S.getError();
  return {};
}
if (!S->isDirectory()) {
  EC = std::error_code(static_cast<int>(errc::not_a_directory),
                       std::system_category());
  return {};
}

auto *D = cast<RedirectingFileSystem::RedirectingDirectoryEntry>(*E);
return directory_iterator(std::make_shared<VFSFromYamlDirIterImpl>(
    Dir, D->contents_begin(), D->contents_end(),
    /*IterateExternalFS=*/shouldUseExternalFS(), *ExternalFS, EC));
1150}

1152void RedirectingFileSystem::setExternalContentsPrefixDir(StringRef PrefixDir) {
ExternalContentsPrefixDir = PrefixDir.str();
1154}

1156StringRef RedirectingFileSystem::getExternalContentsPrefixDir() const {
return ExternalContentsPrefixDir;
1158}

1160void RedirectingFileSystem::setFallthrough(bool Fallthrough) {
IsFallthrough = Fallthrough;
1162}

1164std::vector<StringRef> RedirectingFileSystem::getRoots() const {
std::vector<StringRef> R;
for (const auto &Root : Roots)
  R.push_back(Root->getName());
return R;
1169}

1171void RedirectingFileSystem::dump(raw_ostream &OS) const {
for (const auto &Root : Roots)
  dumpEntry(OS, Root.get());
1174}

1176void RedirectingFileSystem::dumpEntry(raw_ostream &OS,
                                    RedirectingFileSystem::Entry *E,
                                    int NumSpaces) const {
StringRef Name = E->getName();
for (int i = 0, e = NumSpaces; i < e; ++i)
  OS << " ";
OS << "'" << Name.str().c_str() << "'"
   << "\n";

if (E->getKind() == RedirectingFileSystem::EK_Directory) {
  auto *DE = dyn_cast<RedirectingFileSystem::RedirectingDirectoryEntry>(E);
  assert(DE && "Should be a directory")((DE && "Should be a directory") ? static_cast<void
> (0) : __assert_fail ("DE && \"Should be a directory\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1187, __PRETTY_FUNCTION__));

  for (std::unique_ptr<Entry> &SubEntry :
       llvm::make_range(DE->contents_begin(), DE->contents_end()))
    dumpEntry(OS, SubEntry.get(), NumSpaces + 2);
}
1193}

1195#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
1196LLVM_DUMP_METHOD__attribute__((noinline)) __attribute__((__used__)) void RedirectingFileSystem::dump() const { dump(dbgs()); }
1197#endif

1199/// A helper class to hold the common YAML parsing state.
1200class llvm::vfs::RedirectingFileSystemParser {
yaml::Stream &Stream;

void error(yaml::Node *N, const Twine &Msg) { Stream.printError(N, Msg); }

// false on error
bool parseScalarString(yaml::Node *N, StringRef &Result,
                       SmallVectorImpl<char> &Storage) {
  const auto *S = dyn_cast<yaml::ScalarNode>(N);

  if (!S) {
    error(N, "expected string");
    return false;
  }
  Result = S->getValue(Storage);
  return true;
}

// false on error
bool parseScalarBool(yaml::Node *N, bool &Result) {
  SmallString<5> Storage;
  StringRef Value;
  if (!parseScalarString(N, Value, Storage))
    return false;

  if (Value.equals_lower("true") || Value.equals_lower("on") ||
      Value.equals_lower("yes") || Value == "1") {
    Result = true;
    return true;
  } else if (Value.equals_lower("false") || Value.equals_lower("off") ||
             Value.equals_lower("no") || Value == "0") {
    Result = false;
    return true;
  }

  error(N, "expected boolean value");
  return false;
}

struct KeyStatus {
  bool Required;
  bool Seen = false;

  KeyStatus(bool Required = false) : Required(Required) {}
};

using KeyStatusPair = std::pair<StringRef, KeyStatus>;

// false on error
bool checkDuplicateOrUnknownKey(yaml::Node *KeyNode, StringRef Key,
                                DenseMap<StringRef, KeyStatus> &Keys) {
  if (!Keys.count(Key)) {
    error(KeyNode, "unknown key");
    return false;
  }
  KeyStatus &S = Keys[Key];
  if (S.Seen) {
    error(KeyNode, Twine("duplicate key '") + Key + "'");
    return false;
  }
  S.Seen = true;
  return true;
}

// false on error
bool checkMissingKeys(yaml::Node *Obj, DenseMap<StringRef, KeyStatus> &Keys) {
  for (const auto &I : Keys) {
    if (I.second.Required && !I.second.Seen) {
      error(Obj, Twine("missing key '") + I.first + "'");
      return false;
    }
  }
  return true;
}

RedirectingFileSystem::Entry *
lookupOrCreateEntry(RedirectingFileSystem *FS, StringRef Name,
                    RedirectingFileSystem::Entry *ParentEntry = nullptr) {
  if (!ParentEntry) { // Look for a existent root
    for (const auto &Root : FS->Roots) {
      if (Name.equals(Root->getName())) {
        ParentEntry = Root.get();
        return ParentEntry;
      }
    }
  } else { // Advance to the next component
    auto *DE = dyn_cast<RedirectingFileSystem::RedirectingDirectoryEntry>(
        ParentEntry);
    for (std::unique_ptr<RedirectingFileSystem::Entry> &Content :
         llvm::make_range(DE->contents_begin(), DE->contents_end())) {
      auto *DirContent =
          dyn_cast<RedirectingFileSystem::RedirectingDirectoryEntry>(
              Content.get());
      if (DirContent && Name.equals(Content->getName()))
        return DirContent;
    }
  }

  // ... or create a new one
  std::unique_ptr<RedirectingFileSystem::Entry> E =
      std::make_unique<RedirectingFileSystem::RedirectingDirectoryEntry>(
          Name, Status("", getNextVirtualUniqueID(),
                       std::chrono::system_clock::now(), 0, 0, 0,
                       file_type::directory_file, sys::fs::all_all));

  if (!ParentEntry) { // Add a new root to the overlay
    FS->Roots.push_back(std::move(E));
    ParentEntry = FS->Roots.back().get();
    return ParentEntry;
  }

  auto *DE =
      cast<RedirectingFileSystem::RedirectingDirectoryEntry>(ParentEntry);
  DE->addContent(std::move(E));
  return DE->getLastContent();
}

void uniqueOverlayTree(RedirectingFileSystem *FS,
                       RedirectingFileSystem::Entry *SrcE,
                       RedirectingFileSystem::Entry *NewParentE = nullptr) {
  StringRef Name = SrcE->getName();
  switch (SrcE->getKind()) {
  case RedirectingFileSystem::EK_Directory: {
    auto *DE = cast<RedirectingFileSystem::RedirectingDirectoryEntry>(SrcE);
    // Empty directories could be present in the YAML as a way to
    // describe a file for a current directory after some of its subdir
    // is parsed. This only leads to redundant walks, ignore it.
    if (!Name.empty())
      NewParentE = lookupOrCreateEntry(FS, Name, NewParentE);
    for (std::unique_ptr<RedirectingFileSystem::Entry> &SubEntry :
         llvm::make_range(DE->contents_begin(), DE->contents_end()))
      uniqueOverlayTree(FS, SubEntry.get(), NewParentE);
    break;
  }
  case RedirectingFileSystem::EK_File: {
    assert(NewParentE && "Parent entry must exist")((NewParentE && "Parent entry must exist") ? static_cast
<void> (0) : __assert_fail ("NewParentE && \"Parent entry must exist\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1335, __PRETTY_FUNCTION__));
    auto *FE = cast<RedirectingFileSystem::RedirectingFileEntry>(SrcE);
    auto *DE =
        cast<RedirectingFileSystem::RedirectingDirectoryEntry>(NewParentE);
    DE->addContent(
        std::make_unique<RedirectingFileSystem::RedirectingFileEntry>(
            Name, FE->getExternalContentsPath(), FE->getUseName()));
    break;
  }
  }
}

std::unique_ptr<RedirectingFileSystem::Entry>
parseEntry(yaml::Node *N, RedirectingFileSystem *FS, bool IsRootEntry) {
  auto *M = dyn_cast<yaml::MappingNode>(N);
  if (!M) {
    error(N, "expected mapping node for file or directory entry");
    return nullptr;
  }

  KeyStatusPair Fields[] = {
      KeyStatusPair("name", true),
      KeyStatusPair("type", true),
      KeyStatusPair("contents", false),
      KeyStatusPair("external-contents", false),
      KeyStatusPair("use-external-name", false),
  };

  DenseMap<StringRef, KeyStatus> Keys(std::begin(Fields), std::end(Fields));

  bool HasContents = false; // external or otherwise
  std::vector<std::unique_ptr<RedirectingFileSystem::Entry>>
      EntryArrayContents;
  SmallString<256> ExternalContentsPath;
  SmallString<256> Name;
  yaml::Node *NameValueNode = nullptr;
  auto UseExternalName =
      RedirectingFileSystem::RedirectingFileEntry::NK_NotSet;
  RedirectingFileSystem::EntryKind Kind;

  for (auto &I : *M) {
    StringRef Key;
    // Reuse the buffer for key and value, since we don't look at key after
    // parsing value.
    SmallString<256> Buffer;
    if (!parseScalarString(I.getKey(), Key, Buffer))
      return nullptr;

    if (!checkDuplicateOrUnknownKey(I.getKey(), Key, Keys))
      return nullptr;

    StringRef Value;
    if (Key == "name") {
      if (!parseScalarString(I.getValue(), Value, Buffer))
        return nullptr;

      NameValueNode = I.getValue();
      // Guarantee that old YAML files containing paths with ".." and "."
      // are properly canonicalized before read into the VFS.
      Name = canonicalize(Value).str();
    } else if (Key == "type") {
      if (!parseScalarString(I.getValue(), Value, Buffer))
        return nullptr;
      if (Value == "file")
        Kind = RedirectingFileSystem::EK_File;
      else if (Value == "directory")
        Kind = RedirectingFileSystem::EK_Directory;
      else {
        error(I.getValue(), "unknown value for 'type'");
        return nullptr;
      }
    } else if (Key == "contents") {
      if (HasContents) {
        error(I.getKey(),
              "entry already has 'contents' or 'external-contents'");
        return nullptr;
      }
      HasContents = true;
      auto *Contents = dyn_cast<yaml::SequenceNode>(I.getValue());
      if (!Contents) {
        // FIXME: this is only for directories, what about files?
        error(I.getValue(), "expected array");
        return nullptr;
      }

      for (auto &I : *Contents) {
        if (std::unique_ptr<RedirectingFileSystem::Entry> E =
                parseEntry(&I, FS, /*IsRootEntry*/ false))
          EntryArrayContents.push_back(std::move(E));
        else
          return nullptr;
      }
    } else if (Key == "external-contents") {
      if (HasContents) {
        error(I.getKey(),
              "entry already has 'contents' or 'external-contents'");
        return nullptr;
      }
      HasContents = true;
      if (!parseScalarString(I.getValue(), Value, Buffer))
        return nullptr;

      SmallString<256> FullPath;
      if (FS->IsRelativeOverlay) {
        FullPath = FS->getExternalContentsPrefixDir();
        assert(!FullPath.empty() &&((!FullPath.empty() && "External contents prefix directory must exist"
) ? static_cast<void> (0) : __assert_fail ("!FullPath.empty() && \"External contents prefix directory must exist\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1441, __PRETTY_FUNCTION__))
               "External contents prefix directory must exist")((!FullPath.empty() && "External contents prefix directory must exist"
) ? static_cast<void> (0) : __assert_fail ("!FullPath.empty() && \"External contents prefix directory must exist\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1441, __PRETTY_FUNCTION__));
        llvm::sys::path::append(FullPath, Value);
      } else {
        FullPath = Value;
      }

      // Guarantee that old YAML files containing paths with ".." and "."
      // are properly canonicalized before read into the VFS.
      FullPath = canonicalize(FullPath);
      ExternalContentsPath = FullPath.str();
    } else if (Key == "use-external-name") {
      bool Val;
      if (!parseScalarBool(I.getValue(), Val))
        return nullptr;
      UseExternalName =
          Val ? RedirectingFileSystem::RedirectingFileEntry::NK_External
              : RedirectingFileSystem::RedirectingFileEntry::NK_Virtual;
    } else {
      llvm_unreachable("key missing from Keys")::llvm::llvm_unreachable_internal("key missing from Keys", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1459);
    }
  }

  if (Stream.failed())
    return nullptr;

  // check for missing keys
  if (!HasContents) {
    error(N, "missing key 'contents' or 'external-contents'");
    return nullptr;
  }
  if (!checkMissingKeys(N, Keys))
    return nullptr;

  // check invalid configuration
  if (Kind == RedirectingFileSystem::EK_Directory &&
      UseExternalName !=
          RedirectingFileSystem::RedirectingFileEntry::NK_NotSet) {
    error(N, "'use-external-name' is not supported for directories");
    return nullptr;
  }

  sys::path::Style path_style = sys::path::Style::native;
  if (IsRootEntry) {
    // VFS root entries may be in either Posix or Windows style.  Figure out
    // which style we have, and use it consistently.
    if (sys::path::is_absolute(Name, sys::path::Style::posix)) {
      path_style = sys::path::Style::posix;
    } else if (sys::path::is_absolute(Name, sys::path::Style::windows)) {
      path_style = sys::path::Style::windows;
    } else {
      assert(NameValueNode && "Name presence should be checked earlier")((NameValueNode && "Name presence should be checked earlier"
) ? static_cast<void> (0) : __assert_fail ("NameValueNode && \"Name presence should be checked earlier\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1491, __PRETTY_FUNCTION__));
      error(NameValueNode,
            "entry with relative path at the root level is not discoverable");
      return nullptr;
    }
  }

  // Remove trailing slash(es), being careful not to remove the root path
  StringRef Trimmed(Name);
  size_t RootPathLen = sys::path::root_path(Trimmed, path_style).size();
  while (Trimmed.size() > RootPathLen &&
         sys::path::is_separator(Trimmed.back(), path_style))
    Trimmed = Trimmed.slice(0, Trimmed.size() - 1);

  // Get the last component
  StringRef LastComponent = sys::path::filename(Trimmed, path_style);

  std::unique_ptr<RedirectingFileSystem::Entry> Result;
  switch (Kind) {
  case RedirectingFileSystem::EK_File:
    Result = std::make_unique<RedirectingFileSystem::RedirectingFileEntry>(
        LastComponent, std::move(ExternalContentsPath), UseExternalName);
    break;
  case RedirectingFileSystem::EK_Directory:
    Result =
        std::make_unique<RedirectingFileSystem::RedirectingDirectoryEntry>(
            LastComponent, std::move(EntryArrayContents),
            Status("", getNextVirtualUniqueID(),
                   std::chrono::system_clock::now(), 0, 0, 0,
                   file_type::directory_file, sys::fs::all_all));
    break;
  }

  StringRef Parent = sys::path::parent_path(Trimmed, path_style);
  if (Parent.empty())
    return Result;

  // if 'name' contains multiple components, create implicit directory entries
  for (sys::path::reverse_iterator I = sys::path::rbegin(Parent, path_style),
                                   E = sys::path::rend(Parent);
       I != E; ++I) {
    std::vector<std::unique_ptr<RedirectingFileSystem::Entry>> Entries;
    Entries.push_back(std::move(Result));
    Result =
        std::make_unique<RedirectingFileSystem::RedirectingDirectoryEntry>(
            *I, std::move(Entries),
            Status("", getNextVirtualUniqueID(),
                   std::chrono::system_clock::now(), 0, 0, 0,
                   file_type::directory_file, sys::fs::all_all));
  }
  return Result;
}

1544public:
RedirectingFileSystemParser(yaml::Stream &S) : Stream(S) {}

// false on error
bool parse(yaml::Node *Root, RedirectingFileSystem *FS) {
  auto *Top = dyn_cast<yaml::MappingNode>(Root);
  if (!Top) {
    error(Root, "expected mapping node");
    return false;
  }

  KeyStatusPair Fields[] = {
      KeyStatusPair("version", true),
      KeyStatusPair("case-sensitive", false),
      KeyStatusPair("use-external-names", false),
      KeyStatusPair("overlay-relative", false),
      KeyStatusPair("fallthrough", false),
      KeyStatusPair("roots", true),
  };

  DenseMap<StringRef, KeyStatus> Keys(std::begin(Fields), std::end(Fields));
  std::vector<std::unique_ptr<RedirectingFileSystem::Entry>> RootEntries;

  // Parse configuration and 'roots'
  for (auto &I : *Top) {
    SmallString<10> KeyBuffer;
    StringRef Key;
    if (!parseScalarString(I.getKey(), Key, KeyBuffer))
      return false;

    if (!checkDuplicateOrUnknownKey(I.getKey(), Key, Keys))
      return false;

    if (Key == "roots") {
      auto *Roots = dyn_cast<yaml::SequenceNode>(I.getValue());
      if (!Roots) {
        error(I.getValue(), "expected array");
        return false;
      }

      for (auto &I : *Roots) {
        if (std::unique_ptr<RedirectingFileSystem::Entry> E =
                parseEntry(&I, FS, /*IsRootEntry*/ true))
          RootEntries.push_back(std::move(E));
        else
          return false;
      }
    } else if (Key == "version") {
      StringRef VersionString;
      SmallString<4> Storage;
      if (!parseScalarString(I.getValue(), VersionString, Storage))
        return false;
      int Version;
      if (VersionString.getAsInteger<int>(10, Version)) {
        error(I.getValue(), "expected integer");
        return false;
      }
      if (Version < 0) {
        error(I.getValue(), "invalid version number");
        return false;
      }
      if (Version != 0) {
        error(I.getValue(), "version mismatch, expected 0");
        return false;
      }
    } else if (Key == "case-sensitive") {
      if (!parseScalarBool(I.getValue(), FS->CaseSensitive))
        return false;
    } else if (Key == "overlay-relative") {
      if (!parseScalarBool(I.getValue(), FS->IsRelativeOverlay))
        return false;
    } else if (Key == "use-external-names") {
      if (!parseScalarBool(I.getValue(), FS->UseExternalNames))
        return false;
    } else if (Key == "fallthrough") {
      if (!parseScalarBool(I.getValue(), FS->IsFallthrough))
        return false;
    } else {
      llvm_unreachable("key missing from Keys")::llvm::llvm_unreachable_internal("key missing from Keys", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1622);
    }
  }

  if (Stream.failed())
    return false;

  if (!checkMissingKeys(Top, Keys))
    return false;

  // Now that we sucessefully parsed the YAML file, canonicalize the internal
  // representation to a proper directory tree so that we can search faster
  // inside the VFS.
  for (auto &E : RootEntries)
    uniqueOverlayTree(FS, E.get());

  return true;
}
1640};

1642RedirectingFileSystem *
1643RedirectingFileSystem::create(std::unique_ptr<MemoryBuffer> Buffer,
                            SourceMgr::DiagHandlerTy DiagHandler,
                            StringRef YAMLFilePath, void *DiagContext,
                            IntrusiveRefCntPtr<FileSystem> ExternalFS) {
SourceMgr SM;
yaml::Stream Stream(Buffer->getMemBufferRef(), SM);

SM.setDiagHandler(DiagHandler, DiagContext);
yaml::document_iterator DI = Stream.begin();
yaml::Node *Root = DI->getRoot();
if (DI == Stream.end() || !Root) {
2
←
Assuming 'Root' is non-null→
3
←
Taking false branch→
  SM.PrintMessage(SMLoc(), SourceMgr::DK_Error, "expected root node");
  return nullptr;
}

RedirectingFileSystemParser P(Stream);

std::unique_ptr<RedirectingFileSystem> FS(
    new RedirectingFileSystem(ExternalFS));
4
←
Memory is allocated→

if (!YAMLFilePath.empty()) {
5
←
Assuming the condition is false→
6
←
Taking false branch→
  // Use the YAML path from -ivfsoverlay to compute the dir to be prefixed
  // to each 'external-contents' path.
  //
  // Example:
  //    -ivfsoverlay dummy.cache/vfs/vfs.yaml
  // yields:
  //  FS->ExternalContentsPrefixDir => /<absolute_path_to>/dummy.cache/vfs
  //
  SmallString<256> OverlayAbsDir = sys::path::parent_path(YAMLFilePath);
  std::error_code EC = llvm::sys::fs::make_absolute(OverlayAbsDir);
  assert(!EC && "Overlay dir final path must be absolute")((!EC && "Overlay dir final path must be absolute") ?
 static_cast<void> (0) : __assert_fail ("!EC && \"Overlay dir final path must be absolute\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1674, __PRETTY_FUNCTION__));
  (void)EC;
  FS->setExternalContentsPrefixDir(OverlayAbsDir);
}

if (!P.parse(Root, FS.get()))
7
←
Taking false branch→
  return nullptr;

return FS.release();
1683}

1685ErrorOr<RedirectingFileSystem::Entry *>
1686RedirectingFileSystem::lookupPath(const Twine &Path_) const {
SmallString<256> Path;
Path_.toVector(Path);

// Handle relative paths
if (std::error_code EC = makeAbsolute(Path))
  return EC;

// Canonicalize path by removing ".", "..", "./", components. This is
// a VFS request, do not bother about symlinks in the path components
// but canonicalize in order to perform the correct entry search.
Path = canonicalize(Path);
if (Path.empty())
  return make_error_code(llvm::errc::invalid_argument);

sys::path::const_iterator Start = sys::path::begin(Path);
sys::path::const_iterator End = sys::path::end(Path);
for (const auto &Root : Roots) {
  ErrorOr<RedirectingFileSystem::Entry *> Result =
      lookupPath(Start, End, Root.get());
  if (Result || Result.getError() != llvm::errc::no_such_file_or_directory)
    return Result;
}
return make_error_code(llvm::errc::no_such_file_or_directory);
1710}

1712ErrorOr<RedirectingFileSystem::Entry *>
1713RedirectingFileSystem::lookupPath(sys::path::const_iterator Start,
                                sys::path::const_iterator End,
                                RedirectingFileSystem::Entry *From) const {
assert(!isTraversalComponent(*Start) &&((!isTraversalComponent(*Start) && !isTraversalComponent
(From->getName()) && "Paths should not contain traversal components"
) ? static_cast<void> (0) : __assert_fail ("!isTraversalComponent(*Start) && !isTraversalComponent(From->getName()) && \"Paths should not contain traversal components\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1718, __PRETTY_FUNCTION__))
       !isTraversalComponent(From->getName()) &&((!isTraversalComponent(*Start) && !isTraversalComponent
(From->getName()) && "Paths should not contain traversal components"
) ? static_cast<void> (0) : __assert_fail ("!isTraversalComponent(*Start) && !isTraversalComponent(From->getName()) && \"Paths should not contain traversal components\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1718, __PRETTY_FUNCTION__))
       "Paths should not contain traversal components")((!isTraversalComponent(*Start) && !isTraversalComponent
(From->getName()) && "Paths should not contain traversal components"
) ? static_cast<void> (0) : __assert_fail ("!isTraversalComponent(*Start) && !isTraversalComponent(From->getName()) && \"Paths should not contain traversal components\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1718, __PRETTY_FUNCTION__));

StringRef FromName = From->getName();

// Forward the search to the next component in case this is an empty one.
if (!FromName.empty()) {
  if (!pathComponentMatches(*Start, FromName))
    return make_error_code(llvm::errc::no_such_file_or_directory);

  ++Start;

  if (Start == End) {
    // Match!
    return From;
  }
}

auto *DE = dyn_cast<RedirectingFileSystem::RedirectingDirectoryEntry>(From);
if (!DE)
  return make_error_code(llvm::errc::not_a_directory);

for (const std::unique_ptr<RedirectingFileSystem::Entry> &DirEntry :
     llvm::make_range(DE->contents_begin(), DE->contents_end())) {
  ErrorOr<RedirectingFileSystem::Entry *> Result =
      lookupPath(Start, End, DirEntry.get());
  if (Result || Result.getError() != llvm::errc::no_such_file_or_directory)
    return Result;
}

return make_error_code(llvm::errc::no_such_file_or_directory);
1748}

1750static Status getRedirectedFileStatus(const Twine &Path, bool UseExternalNames,
                                    Status ExternalStatus) {
Status S = ExternalStatus;
if (!UseExternalNames)
  S = Status::copyWithNewName(S, Path);
S.IsVFSMapped = true;
return S;
1757}

1759ErrorOr<Status> RedirectingFileSystem::status(const Twine &Path,
                                            RedirectingFileSystem::Entry *E) {
assert(E != nullptr)((E != nullptr) ? static_cast<void> (0) : __assert_fail
 ("E != nullptr", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1761, __PRETTY_FUNCTION__));
if (auto *F = dyn_cast<RedirectingFileSystem::RedirectingFileEntry>(E)) {
  ErrorOr<Status> S = ExternalFS->status(F->getExternalContentsPath());
  assert(!S || S->getName() == F->getExternalContentsPath())((!S || S->getName() == F->getExternalContentsPath()) ?
 static_cast<void> (0) : __assert_fail ("!S || S->getName() == F->getExternalContentsPath()"
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1764, __PRETTY_FUNCTION__));
  if (S)
    return getRedirectedFileStatus(Path, F->useExternalName(UseExternalNames),
                                   *S);
  return S;
} else { // directory
  auto *DE = cast<RedirectingFileSystem::RedirectingDirectoryEntry>(E);
  return Status::copyWithNewName(DE->getStatus(), Path);
}
1773}

1775ErrorOr<Status> RedirectingFileSystem::status(const Twine &Path) {
ErrorOr<RedirectingFileSystem::Entry *> Result = lookupPath(Path);
if (!Result) {
  if (shouldUseExternalFS() &&
      Result.getError() == llvm::errc::no_such_file_or_directory) {
    return ExternalFS->status(Path);
  }
  return Result.getError();
}
return status(Path, *Result);
1785}

1787namespace {

1789/// Provide a file wrapper with an overriden status.
1790class FileWithFixedStatus : public File {
std::unique_ptr<File> InnerFile;
Status S;

1794public:
FileWithFixedStatus(std::unique_ptr<File> InnerFile, Status S)
    : InnerFile(std::move(InnerFile)), S(std::move(S)) {}

ErrorOr<Status> status() override { return S; }
ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>

getBuffer(const Twine &Name, int64_t FileSize, bool RequiresNullTerminator,
          bool IsVolatile) override {
  return InnerFile->getBuffer(Name, FileSize, RequiresNullTerminator,
                              IsVolatile);
}

std::error_code close() override { return InnerFile->close(); }
1808};

1810} // namespace

1812ErrorOr<std::unique_ptr<File>>
1813RedirectingFileSystem::openFileForRead(const Twine &Path) {
ErrorOr<RedirectingFileSystem::Entry *> E = lookupPath(Path);
if (!E) {
  if (shouldUseExternalFS() &&
      E.getError() == llvm::errc::no_such_file_or_directory) {
    return ExternalFS->openFileForRead(Path);
  }
  return E.getError();
}

auto *F = dyn_cast<RedirectingFileSystem::RedirectingFileEntry>(*E);
if (!F) // FIXME: errc::not_a_file?
  return make_error_code(llvm::errc::invalid_argument);

auto Result = ExternalFS->openFileForRead(F->getExternalContentsPath());
if (!Result)
  return Result;

auto ExternalStatus = (*Result)->status();
if (!ExternalStatus)
  return ExternalStatus.getError();

// FIXME: Update the status with the name and VFSMapped.
Status S = getRedirectedFileStatus(Path, F->useExternalName(UseExternalNames),
                                   *ExternalStatus);
return std::unique_ptr<File>(
    std::make_unique<FileWithFixedStatus>(std::move(*Result), S));
1840}

1842std::error_code
1843RedirectingFileSystem::getRealPath(const Twine &Path,
                                 SmallVectorImpl<char> &Output) const {
ErrorOr<RedirectingFileSystem::Entry *> Result = lookupPath(Path);
if (!Result) {
  if (shouldUseExternalFS() &&
      Result.getError() == llvm::errc::no_such_file_or_directory) {
    return ExternalFS->getRealPath(Path, Output);
  }
  return Result.getError();
}

if (auto *F =
        dyn_cast<RedirectingFileSystem::RedirectingFileEntry>(*Result)) {
  return ExternalFS->getRealPath(F->getExternalContentsPath(), Output);
}
// Even if there is a directory entry, fall back to ExternalFS if allowed,
// because directories don't have a single external contents path.
return shouldUseExternalFS() ? ExternalFS->getRealPath(Path, Output)
                             : llvm::errc::invalid_argument;
1862}

1864IntrusiveRefCntPtr<FileSystem>
1865vfs::getVFSFromYAML(std::unique_ptr<MemoryBuffer> Buffer,
                  SourceMgr::DiagHandlerTy DiagHandler,
                  StringRef YAMLFilePath, void *DiagContext,
                  IntrusiveRefCntPtr<FileSystem> ExternalFS) {
return RedirectingFileSystem::create(std::move(Buffer), DiagHandler,
                                     YAMLFilePath, DiagContext,
                                     std::move(ExternalFS));
1872}

1874static void getVFSEntries(RedirectingFileSystem::Entry *SrcE,
                        SmallVectorImpl<StringRef> &Path,
                        SmallVectorImpl<YAMLVFSEntry> &Entries) {
auto Kind = SrcE->getKind();
if (Kind == RedirectingFileSystem::EK_Directory) {
  auto *DE = dyn_cast<RedirectingFileSystem::RedirectingDirectoryEntry>(SrcE);
  assert(DE && "Must be a directory")((DE && "Must be a directory") ? static_cast<void>
 (0) : __assert_fail ("DE && \"Must be a directory\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1880, __PRETTY_FUNCTION__));
  for (std::unique_ptr<RedirectingFileSystem::Entry> &SubEntry :
       llvm::make_range(DE->contents_begin(), DE->contents_end())) {
    Path.push_back(SubEntry->getName());
    getVFSEntries(SubEntry.get(), Path, Entries);
    Path.pop_back();
  }
  return;
}

assert(Kind == RedirectingFileSystem::EK_File && "Must be a EK_File")((Kind == RedirectingFileSystem::EK_File && "Must be a EK_File"
) ? static_cast<void> (0) : __assert_fail ("Kind == RedirectingFileSystem::EK_File && \"Must be a EK_File\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1890, __PRETTY_FUNCTION__));
auto *FE = dyn_cast<RedirectingFileSystem::RedirectingFileEntry>(SrcE);
assert(FE && "Must be a file")((FE && "Must be a file") ? static_cast<void> (
0) : __assert_fail ("FE && \"Must be a file\"", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1892, __PRETTY_FUNCTION__));
SmallString<128> VPath;
for (auto &Comp : Path)
  llvm::sys::path::append(VPath, Comp);
Entries.push_back(YAMLVFSEntry(VPath.c_str(), FE->getExternalContentsPath()));
1897}

1899void vfs::collectVFSFromYAML(std::unique_ptr<MemoryBuffer> Buffer,
                           SourceMgr::DiagHandlerTy DiagHandler,
                           StringRef YAMLFilePath,
                           SmallVectorImpl<YAMLVFSEntry> &CollectedEntries,
                           void *DiagContext,
                           IntrusiveRefCntPtr<FileSystem> ExternalFS) {
RedirectingFileSystem *VFS = RedirectingFileSystem::create(
1
Calling 'RedirectingFileSystem::create'→
8
←
Returned allocated memory→
    std::move(Buffer), DiagHandler, YAMLFilePath, DiagContext,
    std::move(ExternalFS));
ErrorOr<RedirectingFileSystem::Entry *> RootE = VFS->lookupPath("/");
9
←
Potential leak of memory pointed to by 'VFS'
if (!RootE)
  return;
SmallVector<StringRef, 8> Components;
Components.push_back("/");
getVFSEntries(*RootE, Components, CollectedEntries);
1914}

1916UniqueID vfs::getNextVirtualUniqueID() {
static std::atomic<unsigned> UID;
unsigned ID = ++UID;
// The following assumes that uint64_t max will never collide with a real
// dev_t value from the OS.
return UniqueID(std::numeric_limits<uint64_t>::max(), ID);
1922}

1924void YAMLVFSWriter::addEntry(StringRef VirtualPath, StringRef RealPath,
                           bool IsDirectory) {
assert(sys::path::is_absolute(VirtualPath) && "virtual path not absolute")((sys::path::is_absolute(VirtualPath) && "virtual path not absolute"
) ? static_cast<void> (0) : __assert_fail ("sys::path::is_absolute(VirtualPath) && \"virtual path not absolute\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1926, __PRETTY_FUNCTION__));
assert(sys::path::is_absolute(RealPath) && "real path not absolute")((sys::path::is_absolute(RealPath) && "real path not absolute"
) ? static_cast<void> (0) : __assert_fail ("sys::path::is_absolute(RealPath) && \"real path not absolute\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1927, __PRETTY_FUNCTION__));
assert(!pathHasTraversal(VirtualPath) && "path traversal is not supported")((!pathHasTraversal(VirtualPath) && "path traversal is not supported"
) ? static_cast<void> (0) : __assert_fail ("!pathHasTraversal(VirtualPath) && \"path traversal is not supported\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1928, __PRETTY_FUNCTION__));
Mappings.emplace_back(VirtualPath, RealPath, IsDirectory);
1930}

1932void YAMLVFSWriter::addFileMapping(StringRef VirtualPath, StringRef RealPath) {
addEntry(VirtualPath, RealPath, /*IsDirectory=*/false);
1934}

1936void YAMLVFSWriter::addDirectoryMapping(StringRef VirtualPath,
                                      StringRef RealPath) {
addEntry(VirtualPath, RealPath, /*IsDirectory=*/true);
1939}

1941namespace {

1943class JSONWriter {
llvm::raw_ostream &OS;
SmallVector<StringRef, 16> DirStack;

unsigned getDirIndent() { return 4 * DirStack.size(); }
unsigned getFileIndent() { return 4 * (DirStack.size() + 1); }
bool containedIn(StringRef Parent, StringRef Path);
StringRef containedPart(StringRef Parent, StringRef Path);
void startDirectory(StringRef Path);
void endDirectory();
void writeEntry(StringRef VPath, StringRef RPath);

1955public:
JSONWriter(llvm::raw_ostream &OS) : OS(OS) {}

void write(ArrayRef<YAMLVFSEntry> Entries, Optional<bool> UseExternalNames,
           Optional<bool> IsCaseSensitive, Optional<bool> IsOverlayRelative,
           StringRef OverlayDir);
1961};

1963} // namespace

1965bool JSONWriter::containedIn(StringRef Parent, StringRef Path) {
using namespace llvm::sys;

// Compare each path component.
auto IParent = path::begin(Parent), EParent = path::end(Parent);
for (auto IChild = path::begin(Path), EChild = path::end(Path);
     IParent != EParent && IChild != EChild; ++IParent, ++IChild) {
  if (*IParent != *IChild)
    return false;
}
// Have we exhausted the parent path?
return IParent == EParent;
1977}

1979StringRef JSONWriter::containedPart(StringRef Parent, StringRef Path) {
assert(!Parent.empty())((!Parent.empty()) ? static_cast<void> (0) : __assert_fail
 ("!Parent.empty()", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1980, __PRETTY_FUNCTION__));
assert(containedIn(Parent, Path))((containedIn(Parent, Path)) ? static_cast<void> (0) : __assert_fail
 ("containedIn(Parent, Path)", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 1981, __PRETTY_FUNCTION__));
return Path.slice(Parent.size() + 1, StringRef::npos);
1983}

1985void JSONWriter::startDirectory(StringRef Path) {
StringRef Name =
    DirStack.empty() ? Path : containedPart(DirStack.back(), Path);
DirStack.push_back(Path);
unsigned Indent = getDirIndent();
OS.indent(Indent) << "{\n";
OS.indent(Indent + 2) << "'type': 'directory',\n";
OS.indent(Indent + 2) << "'name': \"" << llvm::yaml::escape(Name) << "\",\n";
OS.indent(Indent + 2) << "'contents': [\n";
1994}

1996void JSONWriter::endDirectory() {
unsigned Indent = getDirIndent();
OS.indent(Indent + 2) << "]\n";
OS.indent(Indent) << "}";

DirStack.pop_back();
2002}

2004void JSONWriter::writeEntry(StringRef VPath, StringRef RPath) {
unsigned Indent = getFileIndent();
OS.indent(Indent) << "{\n";
OS.indent(Indent + 2) << "'type': 'file',\n";
OS.indent(Indent + 2) << "'name': \"" << llvm::yaml::escape(VPath) << "\",\n";
OS.indent(Indent + 2) << "'external-contents': \""
                      << llvm::yaml::escape(RPath) << "\"\n";
OS.indent(Indent) << "}";
2012}

2014void JSONWriter::write(ArrayRef<YAMLVFSEntry> Entries,
                     Optional<bool> UseExternalNames,
                     Optional<bool> IsCaseSensitive,
                     Optional<bool> IsOverlayRelative,
                     StringRef OverlayDir) {
using namespace llvm::sys;

OS << "{\n"
      "  'version': 0,\n";
if (IsCaseSensitive.hasValue())
  OS << "  'case-sensitive': '"
     << (IsCaseSensitive.getValue() ? "true" : "false") << "',\n";
if (UseExternalNames.hasValue())
  OS << "  'use-external-names': '"
     << (UseExternalNames.getValue() ? "true" : "false") << "',\n";
bool UseOverlayRelative = false;
if (IsOverlayRelative.hasValue()) {
  UseOverlayRelative = IsOverlayRelative.getValue();
  OS << "  'overlay-relative': '" << (UseOverlayRelative ? "true" : "false")
     << "',\n";
}
OS << "  'roots': [\n";

if (!Entries.empty()) {
  const YAMLVFSEntry &Entry = Entries.front();

  startDirectory(
    Entry.IsDirectory ? Entry.VPath : path::parent_path(Entry.VPath)
  );

  StringRef RPath = Entry.RPath;
  if (UseOverlayRelative) {
    unsigned OverlayDirLen = OverlayDir.size();
    assert(RPath.substr(0, OverlayDirLen) == OverlayDir &&((RPath.substr(0, OverlayDirLen) == OverlayDir && "Overlay dir must be contained in RPath"
) ? static_cast<void> (0) : __assert_fail ("RPath.substr(0, OverlayDirLen) == OverlayDir && \"Overlay dir must be contained in RPath\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2048, __PRETTY_FUNCTION__))
           "Overlay dir must be contained in RPath")((RPath.substr(0, OverlayDirLen) == OverlayDir && "Overlay dir must be contained in RPath"
) ? static_cast<void> (0) : __assert_fail ("RPath.substr(0, OverlayDirLen) == OverlayDir && \"Overlay dir must be contained in RPath\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2048, __PRETTY_FUNCTION__));
    RPath = RPath.slice(OverlayDirLen, RPath.size());
  }

  bool IsCurrentDirEmpty = true;
  if (!Entry.IsDirectory) {
    writeEntry(path::filename(Entry.VPath), RPath);
    IsCurrentDirEmpty = false;
  }

  for (const auto &Entry : Entries.slice(1)) {
    StringRef Dir =
        Entry.IsDirectory ? Entry.VPath : path::parent_path(Entry.VPath);
    if (Dir == DirStack.back()) {
      if (!IsCurrentDirEmpty) {
        OS << ",\n";
      }
    } else {
      bool IsDirPoppedFromStack = false;
      while (!DirStack.empty() && !containedIn(DirStack.back(), Dir)) {
        OS << "\n";
        endDirectory();
        IsDirPoppedFromStack = true;
      }
      if (IsDirPoppedFromStack || !IsCurrentDirEmpty) {
        OS << ",\n";
      }
      startDirectory(Dir);
      IsCurrentDirEmpty = true;
    }
    StringRef RPath = Entry.RPath;
    if (UseOverlayRelative) {
      unsigned OverlayDirLen = OverlayDir.size();
      assert(RPath.substr(0, OverlayDirLen) == OverlayDir &&((RPath.substr(0, OverlayDirLen) == OverlayDir && "Overlay dir must be contained in RPath"
) ? static_cast<void> (0) : __assert_fail ("RPath.substr(0, OverlayDirLen) == OverlayDir && \"Overlay dir must be contained in RPath\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2082, __PRETTY_FUNCTION__))
             "Overlay dir must be contained in RPath")((RPath.substr(0, OverlayDirLen) == OverlayDir && "Overlay dir must be contained in RPath"
) ? static_cast<void> (0) : __assert_fail ("RPath.substr(0, OverlayDirLen) == OverlayDir && \"Overlay dir must be contained in RPath\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2082, __PRETTY_FUNCTION__));
      RPath = RPath.slice(OverlayDirLen, RPath.size());
    }
    if (!Entry.IsDirectory) {
      writeEntry(path::filename(Entry.VPath), RPath);
      IsCurrentDirEmpty = false;
    }
  }

  while (!DirStack.empty()) {
    OS << "\n";
    endDirectory();
  }
  OS << "\n";
}

OS << "  ]\n"
   << "}\n";
2100}

2102void YAMLVFSWriter::write(llvm::raw_ostream &OS) {
llvm::sort(Mappings, [](const YAMLVFSEntry &LHS, const YAMLVFSEntry &RHS) {
  return LHS.VPath < RHS.VPath;
});

JSONWriter(OS).write(Mappings, UseExternalNames, IsCaseSensitive,
                     IsOverlayRelative, OverlayDir);
2109}

2111VFSFromYamlDirIterImpl::VFSFromYamlDirIterImpl(
  const Twine &_Path,
  RedirectingFileSystem::RedirectingDirectoryEntry::iterator Begin,
  RedirectingFileSystem::RedirectingDirectoryEntry::iterator End,
  bool IterateExternalFS, FileSystem &ExternalFS, std::error_code &EC)
  : Dir(_Path.str()), Current(Begin), End(End),
    IterateExternalFS(IterateExternalFS), ExternalFS(ExternalFS) {
EC = incrementImpl(/*IsFirstTime=*/true);
2119}

2121std::error_code VFSFromYamlDirIterImpl::increment() {
return incrementImpl(/*IsFirstTime=*/false);
2123}

2125std::error_code VFSFromYamlDirIterImpl::incrementExternal() {
assert(!(IsExternalFSCurrent && ExternalDirIter == directory_iterator()) &&((!(IsExternalFSCurrent && ExternalDirIter == directory_iterator
()) && "incrementing past end") ? static_cast<void
> (0) : __assert_fail ("!(IsExternalFSCurrent && ExternalDirIter == directory_iterator()) && \"incrementing past end\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2127, __PRETTY_FUNCTION__))
       "incrementing past end")((!(IsExternalFSCurrent && ExternalDirIter == directory_iterator
()) && "incrementing past end") ? static_cast<void
> (0) : __assert_fail ("!(IsExternalFSCurrent && ExternalDirIter == directory_iterator()) && \"incrementing past end\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2127, __PRETTY_FUNCTION__));
std::error_code EC;
if (IsExternalFSCurrent) {
  ExternalDirIter.increment(EC);
} else if (IterateExternalFS) {
  ExternalDirIter = ExternalFS.dir_begin(Dir, EC);
  IsExternalFSCurrent = true;
  if (EC && EC != errc::no_such_file_or_directory)
    return EC;
  EC = {};
}
if (EC || ExternalDirIter == directory_iterator()) {
  CurrentEntry = directory_entry();
} else {
  CurrentEntry = *ExternalDirIter;
}
return EC;
2144}

2146std::error_code VFSFromYamlDirIterImpl::incrementContent(bool IsFirstTime) {
assert((IsFirstTime || Current != End) && "cannot iterate past end")(((IsFirstTime || Current != End) && "cannot iterate past end"
) ? static_cast<void> (0) : __assert_fail ("(IsFirstTime || Current != End) && \"cannot iterate past end\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2147, __PRETTY_FUNCTION__));
if (!IsFirstTime)
  ++Current;
while (Current != End) {
  SmallString<128> PathStr(Dir);
  llvm::sys::path::append(PathStr, (*Current)->getName());
  sys::fs::file_type Type = sys::fs::file_type::type_unknown;
  switch ((*Current)->getKind()) {
  case RedirectingFileSystem::EK_Directory:
    Type = sys::fs::file_type::directory_file;
    break;
  case RedirectingFileSystem::EK_File:
    Type = sys::fs::file_type::regular_file;
    break;
  }
  CurrentEntry = directory_entry(std::string(PathStr.str()), Type);
  return {};
}
return incrementExternal();
2166}

2168std::error_code VFSFromYamlDirIterImpl::incrementImpl(bool IsFirstTime) {
while (true) {
  std::error_code EC = IsExternalFSCurrent ? incrementExternal()
                                           : incrementContent(IsFirstTime);
  if (EC || CurrentEntry.path().empty())
    return EC;
  StringRef Name = llvm::sys::path::filename(CurrentEntry.path());
  if (SeenNames.insert(Name).second)
    return EC; // name not seen before
}
llvm_unreachable("returned above")::llvm::llvm_unreachable_internal("returned above", "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2178);
2179}

2181vfs::recursive_directory_iterator::recursive_directory_iterator(
  FileSystem &FS_, const Twine &Path, std::error_code &EC)
  : FS(&FS_) {
directory_iterator I = FS->dir_begin(Path, EC);
if (I != directory_iterator()) {
  State = std::make_shared<detail::RecDirIterState>();
  State->Stack.push(I);
}
2189}

2191vfs::recursive_directory_iterator &
2192recursive_directory_iterator::increment(std::error_code &EC) {
assert(FS && State && !State->Stack.empty() && "incrementing past end")((FS && State && !State->Stack.empty() &&
 "incrementing past end") ? static_cast<void> (0) : __assert_fail
 ("FS && State && !State->Stack.empty() && \"incrementing past end\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2193, __PRETTY_FUNCTION__));
assert(!State->Stack.top()->path().empty() && "non-canonical end iterator")((!State->Stack.top()->path().empty() && "non-canonical end iterator"
) ? static_cast<void> (0) : __assert_fail ("!State->Stack.top()->path().empty() && \"non-canonical end iterator\""
, "/build/llvm-toolchain-snapshot-12~++20201208100613+51f3432f4b5/llvm/lib/Support/VirtualFileSystem.cpp"
, 2194, __PRETTY_FUNCTION__));
vfs::directory_iterator End;

if (State->HasNoPushRequest)
  State->HasNoPushRequest = false;
else {
  if (State->Stack.top()->type() == sys::fs::file_type::directory_file) {
    vfs::directory_iterator I = FS->dir_begin(State->Stack.top()->path(), EC);
    if (I != End) {
      State->Stack.push(I);
      return *this;
    }
  }
}

while (!State->Stack.empty() && State->Stack.top().increment(EC) == End)
  State->Stack.pop();

if (State->Stack.empty())
  State.reset(); // end iterator

return *this;
2216}